As a wireless power supply system, generally, a technique using electromagnetic induction and a technique using radio waves are known. On the other hand, in recent years, a technique using a magnetic field resonance mode has been proposed.
Japanese Laid-open Patent Publication No. 2009-501510 discusses the wireless power supply technique using the magnetic field resonance mode, for example, a resonator having a resonant frequency of fr1 is provided in a power transmitting apparatus, and a resonator having a resonant frequency of fr2 is provided in a power receiving apparatus. By synchronizing the resonant frequencies fr1 and fr2, and appropriately adjusting the size and arrangement of the resonators, a magnetic field coupling is generated in which energy may be transferred between the power transmitting apparatus and the power receiving apparatus by the magnetic field resonance mode, and power is wirelessly transmitted from the resonator of the power transmitting apparatus to the resonator of the power receiving apparatus. According to such a wireless power supply technique, power transmission efficiency (energy transfer efficiency) may be several tens of percent, so that the distance between the power transmitting apparatus and the power receiving apparatus may be relatively large, for example, several tens of centimeters or larger for a resonator having a size of several tens of centimeters.